[msan] Intercept fstatat / fstatat64.


git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@190306 91177308-0d34-0410-b5e6-96231b3b80d8
Don't allow a NULL-length file. Try to revert to the buffered version.

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@190359 91177308-0d34-0410-b5e6-96231b3b80d8
[dfsan] Initial set of DFSAN_OPTIONS flags.

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@190379 91177308-0d34-0410-b5e6-96231b3b80d8
Delete unused variables.



git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@190383 91177308-0d34-0410-b5e6-96231b3b80d8
[ASan] Don't crash in DescribeHeapAddress if we don't know the current thread's ID

Also make DescribeThread easier to use.
This was firing on Dr.ASan runs, not sure how to repro InvalidTID in a simple test.

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@190392 91177308-0d34-0410-b5e6-96231b3b80d8